Abhesive pattern detector system

ABSTRACT

A system for detecting the location and uniformity of a coating on a substrate is provided. The process comprises the steps of adding a fluorescent dye material to the coating material, coating the substrate with the fluorescent dye-containing coating material, and viewing the pattern obtained thereby under an ultraviolet light source. A gable-top container employing a nonheat sealing coating containing a fluorescent dye on a portion thereof is described. The fluorescent dye is used to aid in evaluating the location and uniformity of the coating.

I United States Patent n51 3,675,015

Geib July 4, 1972 [54) ABHESIVE PATTERN DETECTOR 3,341,705 9/]967Alburgerm; ..250 7| T SYSTEM 3,510,653 5/1970 Holbrook..... ....250 s3.3uv 2,63l,243 3/1953 Weber et al.. ..250/7] lnvemofl Thomas Ge"),Flonssam, 3,334,799 8/1967 Crawford ..229/17 0 7. W h C T W h. I a]Afslgnee eyer user ompany acoma as Primary Examiner-Archie R. Borchelt[22] Flledi Sept- 2, 1969 Att0meyChristensen & Sanborn [21] Appl. No.:854,440 [57] ABSTRACT [52] U 8 Cl 250/71R 229/3 1 229/17 G A system fordetecting the location and uniformity of a coat- 250/71 i ing on asubstrate is provided. The process comprises the steps [51] Int Cl G0121/16 of adding a fluorescent dye material to the coating material, [58]Field 229/3 1 coating the substrate with the fluorescent dye-containingcoat- 6 ing material, and viewing the pattern obtained thereby under anultraviolet light source. A gable-top container employing a non-heatsealing coating containing a fluorescent dye on a [56] References Citedportion thereof is described. The fluorescent dye is used to aid UNITEDSTATES PATENTS in evaluating the location and uniformity of the coating.

3,] 18,060 H1964 Klein ..250/7l T 4 Claims, 2 Drawing FiguresPATENTEDJuL 4 m2 INVENTOR. 77/0/ 145 5. 6. 75

Anne/Vim ABI-IESIVE PATTERN DETECTOR SYSTEM BACKGROUND OF THE INVENTIONThis invention relates to a process or system for determining thelocation and uniformity of a coating placed on a substrate. Thisinvention further relates to a process of evaluating a coating byincorporating a fluorescent material in said coating and visuallyobserving the location and uniformity of the coating under anultraviolet light source. One particular embodiment of this inventionprovides a system for determining the location and consistency of anabhesive coating placed over a portion of the surface of a gable-toppedcontainer. The abhesive is necessary to facilitate opening the pouringspout of the carton but yet obtain an adequate seal to prevent loss ofthe material in the container before opening.

In the art of construction and use of gable-top type con tainers, suchas are widely used in dairy and fruit juice industries, it is well knownto utilize an abhesive material to facilitate in opening the top andexposing the pouring spout for dispensing of the contents. Such acontainer is thoroughly and carefully described in U.S. Pat. No.3,116,002 to D. 1. Crawford et al., U.S. Pat. No. 3,270,940 to H. B.Egleston et al., and U.S. Pat. No. 3,334,799 to D. J. Crawford, and thedisclosures of those patents are included herein by reference to definethe state of the art. Abhesive materials are defined therein as ananti-adhesive or non-heat sealing material.

Use of the technology known to the prior art has resulted in containerswhich are easily opened by the consumer, but yet maintain a fluid-tightseal during shipping and handling. However, positioning of the abhesivematerial in proper registry with the carton blank has been a problemsince very accurate positioning is required to obtain the desired amountof sealing effect in the gable top. The prior art methods of determiningthe location and uniformity of the abhesive coating have not foundparticular success, since they are destructive testing techniques andtake a considerable length of time to perform. The best known method ofevaluating the coating of abhesive is to remove from the production linerepresentative carton blanks coated with a polymer such as polyethyleneover their entire surface and then coated in the desired locations withan abhesive such as a silicone. The area of abhesive application issmeared with a dye or ink substance which stains or is retained upon thesurface of the polymer coating to a different degree than on the surfaceof the abhesive coating. The pattern which then develops indicates thelocation of the abhesive material and the uniformity of the abhesivecoating. This method is, of course, very time consuming and wastefulsince with today's modern processing techniques many cartons would haveproduced with faulty abhesive coatings thereon in the time that it takesto perform this testing procedure.

It is an object of this invention to provide a rapid, nondestructivetesting technique for evaluating the location and uniformity of anabhesive coating on a substrate. It is a further object of thisinvention to provide a method of evaluating the location and uniformityof a normally transparent coating on a substrate by incorporating afluorescent material in the coating formulation prior to placing thecoating formulation upon the substrate and viewing the coated objectunder ultraviolet light.

FIGURES FIG. 1 shows a perspective view of a dispensing container havinga pouring spout to which the present invention has been applied.

FIG. 2 shows a fragmentary portion of the inside surface of a flat blankof the material from which the container shown in FIG. 1 can be erected.

DESCRIPTION OF THE PREFERRED EMBODIMENT A representation of one form ofthe applicants preferred embodiment of this invention is shown in FIGS.1 and 2. In FIG. I, a tubular container 7 is shown surmounted by theusual gable top I. The pouring spout 6 shown in FIG. I is folded out inposition to dispense the contents of the container 7. FIG. 2 shows aportion of the paperboard blank from which the carton shown in FIG. 1 iserected. The entire surface of both sides of the blank has been coatedwith a thermoplastic resin such as polyethylene or the like which actsto prevent liquid penetration of the carton and when heated, pressedtogether and cooled, serves as the adhesive sealant to keep thecontainer bottom and gable top closed after filling. To assist inopening the gable top, an abhesive material 3 is coated on a carefullycontrolled area of the pouring spout portion of gable top 1. Thisabhesive coating must be properly located on each blank in exactregistry with the pouring spout 6 to facilitate opening of the gable topwhen it is desired to dispense the contents and yet permit an adequateheat seal to be achieved. The abhesive material 3 must be positioned onthe carton blank so that the seal areas 4 can provide a liquid sealalong the ridge 2 of the gable top 1 but yet permit easy opening of thepour spout 6 with little damage to the pouring edge 5. By combining afluorescent dye with the abhesive coating material prior to applicationto the blanks, a nondestructive evaluation of the coating uniformity andlocation can be obtained by exposing the abhesive coated surface toultraviolet light. Any fluorescent compound may be employed which iscompatible with the particular coating material being used. Particularlyuseful fluorescent dyes include the organic substances capable offluorescing and emitting visible light when exposed to radiations havingwavelengths between 2,500 Angstroms and 4,500 Angstroms and preferablyin the range of 3,600 to 3,800 Angstroms. Some of the typicalfluorescent organic substances which are suitable for use in, forexample, polymer-containing coating formulations include the following:

Meta diethylaminophenol phthalein hydrochloride Meta diethylaminophenolsuccin hydrochloride Meta aminophenol phthalein hydrochloride The ethylester of meta monobutylaminophenol phthalein Meta aminophenol phthaleinhydrochloride Di (para dimethylaminophenyl) ketone hydrochloride 2, 3diphenyl N-phenyl quinox-alonium sulphate p,p' di[paminobenzoyl-amino)benzoylamino] stilbene 0,0 di[sodium sulphonate] Metamono-ethylaminophenol phthalein Meta monoethylaminophenol phthaleinhydrochloride Diamino stilbene-di-sulphonic acid (Sodium salt) 2, amino,9(4' aminophenyl) acridonium nitrate 4, amino 1,8 naphthal p-xenyl-imide2,[4' amino 8' carboxynaphthyl (1')] benzimidazole sodium sulfonateDi(dimethylaminophenyl) phenylamino naphthyl methane chloride 4 methyl,7 hydroxy coumarin sodium salt Many of the organic fluorescent materialswhich may be used in the practice of this invention are soldcommercially in various forms under trademarks such as Calcofluor(American Cyanamide Company, Wayne, N.J.), Zyglo (by the Zyglo Company)or Uvitex WNA (CIBA Chemical and Dye Co., Fairlawn, N.J.). The abhesivematerials utilized in the preferred embodiment may be any material whichimparts a nonstick characteristic to the surface of the container beingsealed at the desired locations and which prevents fusion of thethermoplastic polymer coating on the surface of the carton when heated.Suitable materials for this purpose include, among others, highmolecular weight polysiloxane gum such as dimethyl siloxane polymers ofthe general formula (Cl-I S 0 Such siloxane gums typically have amolecular weight exceeding 150,000, and capable of being cured orcrosslinked. Such organo siloxane gums are marketed by variousmanufacturers including, for instance, the Silicone Products Division ofthe General Electric Company. Other abhesive materials such aslacquer-type may be used.

The amount of fluorescent material added to the abhesive or othercoating material is, of course, not critical for purposes imineethylester of detecting the location and uniformity of the coating. Itis necessary only to add enough fluorescent material to permit anobserver to see the coating material containing the fluorescent dye whenviewed under ultraviolet light. Typically, the dye concentration variesfrom 1 part per million up to approximately 1 percent by weight of thecoating material. Lower amounts are, of course, preferred to minimizecost of the abhesive coating.

EXAMPLE An abhesive coating material containing fluorescent dye wasformulated as follows: 0.04 parts of American Cyanamids Calcofluor WhiteRWP Concentrate was added to 100 parts of General Electric abhesiveSS-4076 and thoroughly mixed therein. The above abhesive formulation wascoated upon standard polyethylene coated paperboard milk cartons in themanner taught in the above-cited patents to Crawford and Egleston. Whenviewed under ultraviolet light, the pattern and location of the abhesivewas clearly apparent. In this manner the registry, location, shape anduniformity of the abhesive coating may be quickly and effortlesslydetermined for purposes of making a correction, with little or no wasteof the finished carton products.

This process may, of course, be automated by providing suitablelight-activated apparatus designed to evaluate the fluorescentdye-containing coating. For example, a photocell placed above a set ofopaque patterns having an outline of the desired shape of the abhesivecoating could readily evaluate the presence and possible the extent ofabhesive coating outside that area covered by the opaque patterns. Aphotocell having a small area scanning apparatus would indicate areaswhich have no fluorescence indicating lack of presence of the coatingmaterial.

Many other modifications of and applications for the process will occurto one skilled in the art. These modifications might include for examplethe use of the fluorescent dye in a clear adhesive material when it isdesired to accurately pattern the adhesive material on a substrate.

I claim:

1. In the manufacture of paperboard containers from an elongated arrayof successive blanks of flat foldable paperboard material having athermoplastic resin coating thereon, by the steps of applying anapplicator to localized resin coated surfaces of the blanks which areinwardly spaced from edges of the blanks, and overlaying a coating ofabhesive material on each of the surfaces with the applicator, andthereafter folding each blank into the configuration of a container, andhot pressing together other resin coated surfaces of each such foldedblank to effect a plastic-to-plastic bond between the latter resincoated surfaces in each container, while the aforesaid localized resincoated surfaces of the blanks resist adhesion in the containers due tothe abhesive overlays thereon, the improvement wherein the abhesivematerial has an agent incorporated therein which emits fluorescent lightunder the influence of ultraviolet light, and the presence of theabhesive material outside the aforesaid localized resin coated surfacesof the blanks, is determined byirradiating a selected blank withultraviolet light between the aforesaid abhesive applying and foldingsteps, and monitoring the blank for the emission of fluorescent lightfrom the spaces between the aforesaid localized resin coated surfacesand edges, and the applicator and the blanks successive to the selectedblank in the array, are positioned in relation to one another so thatthe overlays are offset from the edges at a distance or distancesprescribed for the same.

2. The process according to claim 1 wherein gable top liquid containersare fabricated from the blanks, and the abhesive overlays are inwardlyspaced from pouring edges of the pouring spouts of the same, as well asfrom fold lines of the spouts transverse said pouring edges.

3. The process according to claim 1 wherein the agent is an organic dyewhich emits visible li ht under the influence of ultraviolet ightirradiated at wave engths between 2,500 angstroms and 4,500 angstroms.

4. The process according to claim 1 wherein the blanks have apolyethylene resin coating on both sides thereof.

2. The process according to claim 1 wherein gable top liquid containersare fabricated from the blanks, and the abhesive overlays are inwardlyspaced from pouring edges of the pouring spouts of the same, as well asfrom fold lines of the spouts transverse said pouring edges.
 3. Theprocess according to claim 1 wherein the agent is an organic dye whichemits visible light under the influence of ultraviolet light irradiatedat wavelengths between 2,500 angstroms and 4,500 angstroms.
 4. Theprocess according to claim 1 wherein the blanks have a polyethyleneresin coating on both sides thereof.